from docx import Document


doc = Document("test1.docx")
# 这里相当于输入了一个空格，后面等待着文字输入
paragraph3 = doc.add_paragraph()
paragraph3.add_run("我是被加粗了文字块儿").bold = True
paragraph3.add_run(",我是普通文字块儿,")
paragraph3.add_run("我是斜体文字块儿").italic = True
doc.save("test1.docx")